title: Farnesol kinase is involved in farnesol metabolism, ABA signaling and flower development in Arabidopsis.
abstract: Farnesol, which is toxic to plant cells at high concentrations, is sequentially phosphorylated to farnesyl phosphate and farnesyl diphosphate. However, the genes responsible for the sequential phosphorylation of farnesol have not been identified and the physiological role of farnesol phosphorylation has not been fully elucidated. To address these questions, we confirmed the presence of farnesol kinase activity in Arabidopsis (Arabidopsis thaliana) membranes and identified the corresponding gene (At5g58560, FOLK). Heterologous expression in recombinant yeast cells established farnesol as the preferred substrate of the FOLK-encoded kinase. Moreover, loss-of-function mutations in the FOLK gene abolished farnesol kinase activity, caused an abscisic acid-hypersensitive phenotype and promoted the development of supernumerary carpels under water-stress conditions. In wild-type plants, exogenous abscisic acid repressed FOLK gene expression. These observations demonstrate a role for farnesol kinase in negative regulation of abscisic acid signaling, and provide molecular evidence for a link between farnesol metabolism, abiotic stress signaling and flower development.
authors.affiliation: Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007, USA.
authors.forename: A Heather
authors.initials: AH
authors.lastname: Fitzpatrick
authors.forename: Jayaram
authors.initials: J
authors.lastname: Bhandari
authors.forename: Dring N
authors.initials: DN
authors.lastname: Crowell
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics; D005204:Farnesol / Q000378:metabolism*; D035264:Flowers / Q000254:growth & development* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012639:Seeds / Q000254:growth & development; D016415:Sequence Alignment; D015398:Signal Transduction; D013379:Substrate Specificity
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D011994:Recombinant Proteins; D005204:Farnesol; D000040:Abscisic Acid; D017853:Phosphotransferases (Alcohol Group Acceptor); C112478:farnesol kinase